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P2403 OBD-II Trouble Code: EVAP Leak Detection Pump Sense Circuit/Open

Diagnostic Trouble Code (DTC): P2403

P2403 code definition

EVAP Leak Detection Pump Sense Circuit/Open

Related Trouble Codes:

  • P2404: EVAP Leak Detection Pump Sensor Circuit Range/Perf
  • P2405: EVAP Leak Detection Pump Sensor Circuit Low
  • P2406: EVAP Leak Detection Pump Sensor Circuit High
  • P2407: EVAP Leak Detection Pump Sensor Circuit Interm/Erratic

What the P2403 code means

The P2403 diagnostic trouble code (DTC) is an indication that the evaporative emission (EVAP) control system leak detection pump sensor has an open circuit.

The purpose of the evaporative emission (EVAP) control system is to protect drivers, passengers, and the atmosphere from pollutants that would otherwise be expelled into the environment by the engine.The powertrain control module (PCM) receives information from the EVAP system pressure sensor and flow sensor, regarding the voltage readings of the EVAP system pressure and flow.

Vehicle manufacturers predetermine a voltage range for these readings and set them into the PCM, to be used as reference data. The EVAP system pressure and flow voltage readings are expected to stay within this predetermined range. When these EVAP system pressure and flow sensors indicate to the PCM that the voltage readings go outside of this range, the P2403 diagnostic trouble code will be stored and the Check Engine Light will come on.

What causes the P2403 code?

  • Faulty EVAP pressure sensor
  • Faulty EVAP flow sensor
  • Faulty purge control solenoid
  • Faulty EVAP leak detection control solenoid
  • Faulty EVAP leak detection pump motor
  • Loose or missing fuel cap
  • Frayed, broken, or shorted wiring
  • Damaged or corroded connectors
  • Broken or split vacuum hoses
  • Broken or split fuel vapor hoses
  • Cracked or obstructed charcoal canister
  • Faulty PCM

What are the symptoms of the P2403 code?

How does a mechanic diagnose the P2403 code?

  • Uses an OBD-II scanner to collect all DTCs that have been stored by the PCM, and records freeze frame data

  • Inspects the EVAP Leak Detection Pump wiring for frays, breaks, and shorts

  • Inspects the EVAP Leak Detection Pump connectors and pins for damage and corrosion

  • Uses a scan tool to activate the EVAP Leak Detection Pump, and listens to see if it can be heard turning on and off.

  • If the EVAP Leak Detection Pump is not operating properly, uses the scanner to check the EVAP system voltage (this should be done at the EVAP Leak Detection Pump connector)

  • Repairs or replaces any circuits, connectors, or components that are open or shorted (if the EVAP Leak Detection Pump does not turn on when it is activated or if it does not pass these tests, it will need to be replaced)

  • Use the OBD-II scanner to clear any trouble codes and complete a test drive to see if the code comes back

  • If the P2403 trouble code comes back, checks the fuel cap to make sure that it is secured to the fuel inlet properly

  • Inspects vacuum hoses and fuel vapor lines and EVAP vacuum lines for breaks or bends (these lines can be very long so time should be taken when inspecting them; it may be necessary to use a smoke machine to find leaks successfully, especially small leaks that are difficult to see)

  • Uses the OBD-II scanner to clear any trouble codes and complete a test drive to see if the code comes back

    • Diagnose and repair any other EVAP control system diagnostic trouble codes that are present.

Common mistakes when diagnosing the P2403 code

  • Neglecting to test for proper operation of the EVAP control system leak detection pump
  • Neglecting to check for leaks in the vacuum hoses and/or fuel vapor hoses
  • Neglecting to check and/or replace other EVAP control system components
  • Neglecting to check the fuel cap to make sure it is secured properly to the fuel inlet
  • Replacing other EVAP control system components before checking any of the components listed above.

How serious is the P2403 code?

The P2403 diagnostic trouble code is not generally considered serious because there are usually no visible symptoms present during operation of the vehicle. However, since the vehicle will emit more pollutants than it should, it is important to have diagnostics and repairs completed as soon as possible. As with all diagnostic trouble codes, problems with other engine components may occur if an extended period of time passes before addressing the problem.

What repairs can fix the P2403 code?

  • Replacing a faulty EVAP pressure sensor
  • Replacing a faulty EVAP flow sensor
  • Replacing a faulty purge control solenoid
  • Replacing a faulty EVAP leak detection control solenoid
  • Replacing a faulty EVAP leak detection pump motor
  • Making corrections to the fuel cap, if it was not installed properly
  • Replacing a missing fuel cap
  • Repairing or replacing frayed, broken or shorted wiring
  • Repairing or replacing damaged or corroded connectors
  • Repairing or replacing broken or split vacuum hoses
  • Repairing or replacing broken or split fuel vapor hoses
  • Replacing the charcoal canister
  • Diagnosing and repairing other EVAP control system DTCs that have been stored by the PCM
  • Replacing or reprogramming a faulty PCM

Additional comments for consideration regarding the P2403 code

EVAP control system trouble codes can sometimes be difficult to diagnose. It is important to take your time when diagnosing these trouble codes. It is also important to note that some EVAP leaks are so small, they cannot be seen with the naked eye. Using a smoke machine can sometimes be helpful in discovering these leaks and diagnosing the P2403 trouble code.

Need help with a P2403 code?

YourMechanic offers certified mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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